Crystal Structures and Optical Properties of Transparent Ceramics Based on LaAlO3–Sr(Al,Ta)O3 Solid Solution
We fabricated a new series of transparent ceramics based on (1–x)LaAlO3–xSr(Al0.5Ta0.5)O3 solid solution. These transparent ceramics
were obtained by a conventional solid‐state reaction, and the crystal structure and its optical properties were investigated. The X‐ray diffraction (XRD) analyses of the ceramics revealed a cubic perovskite structure with a higher Sr(Al0.5Ta0.5)O3
content (Pm‐3m for x = 0.4–0.6 and Fm‐3m for x = 0.7–1.0), whereas the ceramics contained rhombohedral perovskite phase at x = 0.0–0.3. However, the Raman scattering
study revealed that an Fm‐3m ordered structure was contained above x = 0.2. High transmittance was obtained at the cubic composition (x = 0.4–1.0), and was particularly high at x = 0.5–0.7. It was demonstrated
that these transparent ceramics had both a high refractive index and a high Abbe number (low dispersion). The Abbe number of the x = 0.5 composition, 37.8, was higher than that of Ba(Mg,Ta)O3
system transparent ceramics (~30).